Objects are frequently marked or identified with the intention that the marking be either "permanent" or uniquely characteristic of the object or objects so marked. Examples of such markings include ownership information, serial numbers, licenses, permits, statutorily required information, and certification that an object possesses certain characteristics or conforms to certain statutory requirements.
Various methods are employed to achieve these results. The use of relatively convenient and inexpensive labels presents problems in that, if the label can be switched from one object to another, in a manner that is not readily detectable, the validity of the information contained on the label is subject to question.